TY - JOUR
TI - Sensitive analysis of harmonics on the assessment of thermal diffusivity of building materials of a periodic state
AU - Promis Geoffrey
AU - Douzane Omar
AU - Hamed Haykel Ben
AU - Langlet Thierry
JN - Thermal Science
PY - 2018
VL - 22
IS - 1
SP - 223
EP - 236
PT - Article
AB - Thermal efficiency of buildings requires a perfect knowledge of the thermal  properties of materials which compose building envelope. To this end, the use  of reliable testing methods for thermal diffusivity measurements of buildings  materials is fundamental. Currently, periodic methods are based on the  exploitation of fundamental harmonic, resulting from Fourier series  decomposition. The objective of this paper is to demonstrate that fundamental  is necessary and sufficient in order to characterize the thermal diffusivity.  For those purposes, a sensitive analysis of harmonic contributions from  Fourier series is supported by a substantial experimental campaign. Moreover,  some dissymmetrical tests were carried out in order to highlight the  preponderant influence of fundamental, compared to other harmonics. The  analysis of contributions of harmonics shows that the evolution of thermal  diffusivity is very slightly dependent on the number of harmonics. Then, the  exploitation of fundamental is necessary and sufficient, and the  characterization test protocol is validated by experimental results and by  the comparison with commonly accepted values for these kinds of materials.